Merge branch 'jk/ref-paranoia' into jt/no-abuse-alternate-odb-for-submodules

Merge branch 'jk/ref-paranoia' into jt/no-abuse-alternate-odb-for-submodules

* jk/ref-paranoia: (71 commits)
  refs: drop "broken" flag from for_each_fullref_in()
  ref-filter: drop broken-ref code entirely
  ref-filter: stop setting FILTER_REFS_INCLUDE_BROKEN
  repack, prune: drop GIT_REF_PARANOIA settings
  refs: turn on GIT_REF_PARANOIA by default
  refs: omit dangling symrefs when using GIT_REF_PARANOIA
  refs: add DO_FOR_EACH_OMIT_DANGLING_SYMREFS flag
  refs-internal.h: reorganize DO_FOR_EACH_* flag documentation
  refs-internal.h: move DO_FOR_EACH_* flags next to each other
  t5312: be more assertive about command failure
  t5312: test non-destructive repack
  t5312: create bogus ref as necessary
  t5312: drop "verbose" helper
  t5600: provide detached HEAD for corruption failures
  t5516: don't use HEAD ref for invalid ref-deletion tests
  t7900: clean up some more broken refs
  The eighth batch
  t0000: avoid masking git exit value through pipes
  tree-diff: fix leak when not HAVE_ALLOCA_H
  pack-revindex.h: correct the time complexity descriptions
  ...